水星のエクソスフィア:メッセンジャー (MESSENGER) が初めて水星を通過した時の観測
William E McClintock1, E Todd Bradley, Ronald J Vervack
1Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA. william.mcclintock@lasp.colorado.edu
Science (New York, N.Y.)
|July 5, 2008
まとめ
メッセンジャー メッセンジャー
科学分野:
- 惑星科学は惑星科学である.
- 宇宙物理学 宇宙物理学
- 大気科学 大気科学
背景:
- 水星は,濃厚な大気とは異なる薄いエクソスフィアを持っています.
- 水星の外層の組成とダイナミクスを理解することは,惑星科学にとって極めて重要です.
- 以前の観測は限られていたため,現地測定が必要となった.
研究 の 目的:
- メッセンジャー宇宙船の初飛行中の水星の外層放射を分析するために.
- エクソスフィアの種の空間的変動と分布を調査する.
- 水星のエクソスフィアの生成と維持に責任を負うプロセスを特定する.
主な方法:
- メッセンジャーの水銀大気と表面組成スペクトロメーター (MASCS) を利用した.
- 水星のエクソスフィアのナトリウム,カルシウム,水素の排出量を測定した.
- 飛行中にこれらの元素の空間的変化を分析した.
主要な成果:
- 表面付近のカルシウムとナトリウムとともに,アンチサンワード・ナトリウム・テール・エミッションが検出されました.
- 観測された水素は,惑星の昼側で高空で観測されました.
- 空間的変異は,エクソスフィアの種の複数の源と損失メカニズムを示唆した.
結論:
- 水星のエクソスフィアは,複雑な相互作用によって形作られています.
- 太陽風と磁気圏のプロセスは,外気圏の種分布に大きな影響を与える.
- この発見は,水星の宇宙外動力学と進化についての洞察を提供します.
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